David_
Advanced Member level 2
Hello.
I was going through the steps found at
http://www.simonbramble.co.uk/techa...er_supply/digital_control_of_power_supply.htm
to calculate the values for three resistors used in a scheam to control the output of a regulator.
Anyhow, there is R1, R2 & R3.
It ends up like this:
4.2/R1 + 2.5/R3 = 0.8/R2
Which fills in as
4.2/3.03R3 + 2.5/R3 = 0.8/10kΩ
And from that somehow I should ba able to work out a value for:
R3 = 48.576kΩ
R1 = 147.187kΩ
But I don't understand how 48.576k was derived so I can't take anything from this but I am guessing that its simple and the author felt it to be self explanatory.
I am embarrassingly bad at math and just playing around with the numbers gave nothing please advice.
Regards
I was going through the steps found at
http://www.simonbramble.co.uk/techa...er_supply/digital_control_of_power_supply.htm
to calculate the values for three resistors used in a scheam to control the output of a regulator.
Anyhow, there is R1, R2 & R3.
It ends up like this:
4.2/R1 + 2.5/R3 = 0.8/R2
Which fills in as
4.2/3.03R3 + 2.5/R3 = 0.8/10kΩ
And from that somehow I should ba able to work out a value for:
R3 = 48.576kΩ
R1 = 147.187kΩ
But I don't understand how 48.576k was derived so I can't take anything from this but I am guessing that its simple and the author felt it to be self explanatory.
I am embarrassingly bad at math and just playing around with the numbers gave nothing please advice.
Regards